This Coral-Camp fluorite occurrence is an amalgamation of two showings: the Coral and Camp fluorite ‘prospects’ (Assessment Report 3975), which have been combined because they are similar and only 450 metres apart. The Coral and Camp prospects are situated within the Tam claims just west of the head of Mould Creek, 12 kilometres north of the settlement of Liard River on the Alaska Highway (Assessment Report 3975, Maps 4, 8), in one of the most important areas of fluorite mineralization in British Columbia.
The region is underlain by Lower to Upper Paleozoic, platformal sedimentary rocks of Ancestral North America (Geological Survey of Canada Maps 46-1962, 1712A, 1713A). The Coral-Camp showing is one of many similar fluorite deposits in a 17-kilometre-long belt extending north from Liard Hot Springs Provincial Park. This belt is defined by an open anticline, with a gently south-plunging axis, in the Upper Devonian Besa River Formation, with the Middle Devonian Dunedin Formation exposed in a several-kilometre wide zone in the core of the fold. All the fluorite deposits in the belt are situated at or just above or below the unconformity between these units. The Coral-Camp occurrence is on the east-dipping flank of the anticline.
The Dunedin Formation consists of mid- to dark-grey, massive to thinly-bedded fossiliferous limestone. It is generally exposed in the Teeter and Mould creek valleys, which are characterized by karst and 'mesa and butte' topography. The overlying Besa River Formation is predominantly black shale or slate and argillite, with some calcareous shale and minor, buff-brown dolomitic layers. The unconformity between the units is commonly characterized by brecciation and is very irregular in detail, probably due to an erosional or disconformable relationship between them, or to later faulting along the contact (Assessment Report 3975). The mineral deposits in the Liard fluorite belt generally occur as lenticular replacement bodies or as infillings in breccias in one or both of the units.
The Coral occurrence, on the Tam 23 and 24 claims, is at the limestone-shale contact, which dips gently southwards between 15 and 20 degrees (Assessment Report 3975; Geology, Exploration and Mining in British Columbia 1972). In general, the best mineralization is in limestone breccia, the matrix of which is replacement fluorite and witherite, with minor barite and barytocalcite. The largest surface exposure of mineralization at the Coral is at the west end but it appears to be thin. In the main showings to the east, diamond drilling (hole 72-43) has intersected good thicknesses of mineralized limestone breccia, including 26.5 metres of 39 per cent calcium fluoride (Assessment Report 3975). Several 3-metre-long channel samples assayed up 88 per cent fluorite, and a bulk sample (number 4) assayed 64.88 per cent calcium fluoride (Assessment Report 3840; Geology, Exploration and Mining in British Columbia 1972). The overlying shale breccia has thinner and lower-grade mineralization, including minor witherite. Some high-grade fluorite occurs in limestone substantially below the shale contact and the limestone breccia.
The Camp occurrence, located on the Tam 6 and 21 mineral claims, is also at the Dunedin limestone–Besa River shale contact (Assessment Report 3975; Geology, Exploration and Mining in British Columbia 1972). It is essentially a 45-metres wide area of shale breccia with replacement fluorite and witherite. The underlying limestone is locally brecciated and mineralized with fluorite and barite, or veined with fluorite. Trenching in the surrounding areas has exposed barren shale.
Fission-track studies of fluorite from the Gem prospect 8 kilometres to the south suggest that the age of the mineralization is 332 ± 56 Ma (Open File 1992-16).
In 1972, a semi-continuous channel sample taken from trench 1 yielded a weighted average of 58.5 per cent calcium fluoride over 33.5 metres. A chip-grab sample west of the Coral showing averaged 43 per cent calcium fluoride over 38.1 metres (Assessment Report 34801).
In 2012, a semi-continuous channel sample yielded 23.76 per cent calcium fluoride over 19.55 metres (McCallum, N.G. [2012-12-12]: Technical Report on the Liard Fluorspar Project). A bulk composite sample collected from an outcrop pit yielded 64.88 per cent calcium fluoride; the concentrate measured 93.8 per cent, and the recovery was 95.3 per cent.
In 2013, a gravity survey was performed on the Tam and Coral showings by Aurora Geosciences Ltd. On behalf of Prima Fluorspar Corp.
See the Tam (MINFILE 094M 005) and Gem (MINFILE 094M 002) occurrences for a complete work and exploration history of the area.
